[CP2K:954] Re: SCF goes wrong in QMMM after 37000 steps

[Csilla Varnai]

I'm sorry, I'm new on the list. And no, I don't have enough experience  
with CP2K QMMM module, since I've just started using CP2K. Those are  
my input files. I might have missed out something.
For the fully quantum calculation I experienced a small drift in the  
conserved quantity, 0.002 a.u. over 70000 steps, for the QMMM  
calculation, the conserved quantity increased 3 a.u. over 40000 steps.  
And plotting the conserved quantity for the QMMM calculation shows  
some irregular points where the SCF did not converge (time steps  
37186-37187,37209-37213,37237-37241,37264-37268,37270).
Best regards,

Csilla
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On 16 Apr 2008, at 12:56, Teodoro Laino wrote:

>
>
> On 16 Apr 2008, at 13:50, Csilla Varnai wrote:
>
>>
>> Dear All,
>>
>> I'm running a QMMM simulation for 32 water molecule box with 1 qm
>> molecule, NVE. The energy is not conserved, goes up gradually.  
>> Between
> This is a quite strong claim.. do you have any experience with the
> CP2K QMMM module?
>
>> steps 37186th and 37270 at several steps the SCF goes wrong. It does
>> not converge in 50 steps, the energy increases and then oscillates.
>> Afterwards, it seems to be fine until 40000th step.
>> The QM cell is 10x10x10 Angstrom, density cutoff 300 Ry, time step  
>> 0.5
>> fs, temperature 300 K. As for the SCF, I'm using the default
>> parameters. MAX_ITER is 50. For the other steps, SCF never required
>> more than 20 steps except a few ones, in which case it still remained
>> below 31. Any idea why the SCF went wrong?
> No.. and you rarely will get some help unless you won't post your
> full input file.
>
> Cheers
> Teo
>
>> Thanks very much,
>>
>> Csilla
>>
>>>
>
>
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